A decades-long investigation to unlock genetic clues to bipolar disorder continues to maintain its momentum. Directed by Janice Egeland, Ph.D., professor emerita in the Department of Psychiatry and Behavioral Sciences, the “Genetic and Epidemiologic Study of Major Affective Disorders among Old Order Amish” is searching for a susceptibility and/or protective gene(s) for this devastating mental illness.

In 1987 Egeland and colleagues reported in Nature the possible location of DNA markers predisposing individuals to bipolar affective disorders in a large Amish pedigree. This launched the first use of DNA technology to study a common mental disorder and heralded a new direction for psychiatric genetics.

“Although replication failed, our next step was to ascertain more patients and type more informative markers. We expanded the sample by three new multigenerational families. Recently, my bipolar cell collection was genotyped at Myriad Genetics, using 10,000 SNPs (single nucleotide polymorphisms) per subject, or 4 million SNP genotypes for 400 Amish bipolar patients and relatives,” explains Egeland. SNPs represent variations in DNA that help identify multiple genes associated with complex diseases.

“The genetic work pioneered by the Amish study was 20 years ahead of the field. Finally genetic technology is catching up to locate the genes involved,” says Julio Licinio, M.D., professor and chairman of the Department of Psychiatry and Behavioral Sciences.